Investigation of Compressive Bond Behavior of Steel Rebar Embedded in Concrete With Partial Recycled Aggregate Replacement

This study examines the effect of recycled concrete aggregate (RCA) on the bond strength of concrete and deformed steel bars. Here, 144 push-out tests were performed. Four RCA replacement percentages (i.e. 0%, 30%, 40%, and 50%) and three sizes of deformed steel bars (i.e. 10M, 15M, and 20M) were used. Moreover, the effect of embedment length and concrete cover to bar diameter ratio on the bond strength was considered. It was found that under constant mix proportions, an increase in the bar size and the embedment length to bar diameter ratio lead to a reduction in the bond strength. Like regular concrete, larger concrete cover helps improve the bond behaviour. On an average, specimens made of partial RCA had bond strengths similar to regular concrete. In some cases, 30% replacement of natural aggregate by RCA illustrated the best results among all the mixes. A new formula for calculating the bond strength is proposed based on the test results.